Goals: This mission, like its twin Venera 11, called for a flyby spacecraft and a lander to explore Venus' ionosphere, atmosphere and surface and the interplanetary environment.

Accomplishments: The flyby spacecraft sent back data on the solar wind, gamma-ray bursts, ultraviolet radiation and Venus' ionosphere. It passed the planet at a distance of about 35,000 km (about 22,000 miles). The lander probed Venus' atmosphere during a parachute descent. It touched down about 800 km (about 500 miles) away from its twin. The probe survived for a record at the time of 110 minutes and sent back valuable information, although malfunctions caused its soil analysis instrument and imaging system to fail.